Let's walk through the solution step by step.
We are told that a simple random sample is being conducted from a population where both Jake and Mary are members. The chance of Jake being selected is given as [tex]\(\frac{1}{800}\)[/tex].
In a simple random sample, each member of the population has an equal chance of being selected. This means the probability of selecting any individual member, including Mary, will be the same as the probability of selecting Jake.
Since the chance of Jake being selected is [tex]\(\frac{1}{800}\)[/tex], the chance of Mary being selected will also be [tex]\(\frac{1}{800}\)[/tex].
Therefore, the correct answer is:
A. [tex]\(\frac{1}{800}\)[/tex]
